Rooftop daylighting systems, such as skylights and windows, enjoy popularity with both commercial and residential buildings. Such systems illuminate rooms with natural light and thus reduce the consumption of electricity associated with artificial lighting. They increase the perceived spaciousness of a room and may also be configured to enhance air circulation. Such daylighting systems may be used on many types of roofs, including an inclined shingled roof and a high profile tile application.
Rooftop daylighting systems involve an opening cut through the entire thickness of the roofing structure, including interior ceiling sheetrock, roof sheathing, and the like, between adjacent roof trusses. Typically, to maximize the amount of daylight transmitted, the opening is cut to the inside edges of adjacent roof trusses. In residential construction, for example, such trusses typically are positioned twenty-four inches on center, with twenty-two and a half inches of clear opening between them; to maximize the amount of illumination provided through the skylight, the skylight opening usually would be such twenty-two and a half inches in width.
At an opening so configured, a mounting structure known as a curb is typically constructed for receipt of a skylight or rooftop window itself. In a typical application, such a curb would be constructed of 2×4 or 2×6 stock lumber, with the shorter side edge of the lumber disposed against roof sheathing carried by the roof trusses, and with the longer side edge disposed perpendicular to the plane of the roof. At finishing, the exposed trusses, as well as the interior-facing curb members, are covered with sheetrock (also known as drywall) so as to present an attractive completed light shaft suitable for painting, wallpaper, or other treatments.
Conventionally, the members constituting the curb, such as 2×4 or 2×6 stock lumber, would be constructed in situ by “toenailing” into the roof structure, including the roof sheathing and roof trusses. “Toenailing” involves driving a nail obliquely through the side of the curb lumber into the roof sheathing and/or roof truss. However, toenailing causes difficulties. If the curb frame members are toenailed from the light shaft side of the curb frame member, the nailing and construction must be performed before any finishing sheetrock is installed to the interior of the daylighting system opening. On the other hand, if the toenailing is performed from the exterior side of the curb frame members, care must be taken that the nails are not driven so far through the structure as to protrude through the wooden members into the area to be occupied, or perhaps already occupied, by finishing sheetrock thereby breaking, spaulling, or otherwise damaging the finished surface of the light shaft. Furthermore, it has been found that toenailing from either the interior side or the exterior side requires a large number of nails to produce a resulting rooftop daylighting system that will satisfy wind uplift requirements of governmental entities or recommendations of trade associations such as the American Architectural Manufacturers Association. Considerable labor is also involved in making and installing a curb in a roof opening in situ, and often leads to final products of less than optimal quality.
Flashing is installed around the exterior perimeter of the curb at the roof to provide weatherproofing to the entire system. While adequate water-tight techniques and products have been developed and employed for suitably flashing a skylight opening, the systems are typically more labor intensive and time-consuming at the site. Particularly, such flashing must be installed by a tradesman piece-by-piece while upon the roof. The flashing is typically “mopped in” to the roof sheathing—roofing cement is spread upon the roof sheathing and the flashing pieces are pressed into the cement and nailed to the curb member piece-by-piece.
The problems and difficulties described above generally pertain both to original construction of a daylighting system and to re-construction on an older structure. The problems are exacerbated in a re-roofing application, in which old shingles are removed from a building and new shingles are installed. Typically in such re-roofing efforts, new skylights are installed, either for customer preference to update the skylighting system or to insure water tightness, as older skylights may be damaged from the re-roofing work and thereafter leak. However, replacement of the skylight during re-roofing is difficult. As stated above, typically the flashing is mopped into the roof sheathing and nailed to the curb on original construction. Removal of the old flashing and replacement with new flashing is often necessary to insure weatherproofing, but removal of the old flashing that has been mopped in to the roof sheathing and nailed to the curb tends to damage or destroy the curb. However, in a re-roofing application, the interior to the building has already been finished and used for years. Removing the old curb leaves interior sheetrock that has already been installed into the skylight opening, also referred to as the light shaft—as noted above, such sheetrock usually is used to cover the roof trusses and the curb used at the skylight opening to create the light shaft. To construct a new curb using the materials and techniques heretofore known requires either removal of the sheetrock so that toenailing may be accomplished on the interior side of the new curb frame members, or toenailing from the exterior side with the resultant risk of damaging the sheetrock/drywall from nailing overpenetration. Furthermore, the roofing tradesmen tend to prefer to avoid “inside” work, which is not within their specialty, and therefore prefer to avoid tampering with or repairing the sheetrock/drywall. Moreover, as with an initial application, numerous (for example, eighteen) nails must be used in order to satisfy uplift requirements and recommendations when toenailing is used.
The present invention relates to an improvement upon the known systems and methods for providing a flash curb assembly for rooftop daylighting systems and provides distinct advantages over the conventional systems and methods.